In recent years, in imaging systems such as video cameras, an anti-shake function that prevents vibrations such as camera shake has become indispensable, and various types of anti-shake optical systems have been proposed.
For example, in the video camera disclosed in JP H8-29737A, an optical system for correcting camera shake made of two lenses is placed in front of a zoom lens, and image fluctuations due to camera shake are corrected by shifting one of those lenses perpendicularly with respect to the optical axis.
In the video camera disclosed in JP H7-128619A, a zoom lens made of four lens groups is used, and image fluctuations due to camera shake are corrected by shifting a part of the third lens group made of a plurality of lenses perpendicularly with respect to the optical axis.
However, in the video camera disclosed in JP H8-29737A, since the optical system for correcting camera shake is placed in front of the zoom lens, the lens diameter of the optical system for correcting camera shake becomes large. As a consequence, the video camera itself also becomes larger, and the load on the driving system becomes larger, which is disadvantageous with regard to making the video camera smaller and lighter, and reducing its power consumption.
Furthermore, in the video camera disclosed in JP H7-128619A, image fluctuations due to camera shake are corrected by shifting perpendicularly with respect to the optical axis some of the lenses of the third lens group that is fixed with respect to the image plane, so that it is advantageous with regard to size compared to video cameras in which the optical system for correcting camera shake is placed in front of the zoom lens, but since a part of the third lens group is moved, degradation of chromatic aberration during correction of camera shake cannot be avoided.